Easy to Install: One side with 77mm thread is suitable for the filter thread lens, and the other side part is similar to the rear lens bracket of the camera.l Applicable Models: Macro reverse adapter ring and rear lens protection ri ng set is specially designed for EF mount 77mm filter thread lens and cam eras. Lens Protection: The protection ring can prevent your rear lens mount fro m accidental impact; When you reverse and m ount your lens, installing this adapter then it can protect your lens rear part. It comes with 77mm thread and allows you to attach any 77mm filter to protect the rear lens mount. Macro Lens Converter: The macro reverse ring adapter can make any 77mm lens become the Marco lens on the camera, and greatly increase the macro reproduction range. Aluminium Alloy: Macro reverse adapter ring and rear lens protection ring are made of premium aluminium alloy material, which is durable and sturdy.